Feature: #84594 - Additional parameters to email links

Description

Editors in TYPO3 now have more possibilities to set options when creating a link to a specific email address, in accordance with the "mailto:" protocol.

This way, editors can now pre-fill the fields "subject", "CC", "BCC" and "body" in the TYPO3 backend when creating a link to an email address, which are then percent-encoded to the actual email link.

In addition, the <f:link.email> ViewHelper has the same additional attributes as well:

<f:link.email
   email="foo@bar.tld"
   subject="Check out this website"
   cc="foo@example.com"
   bcc="bar@example.com"
>
     some custom content
</f:link.email>

All of the properties and the link fields are optional.

For custom email links, it is now also possible to restrict the additional options via TCA:

'header_link' => [
    'label' => 'Link',
    'config' => [
        'type' => 'link',
        'allowedTypes' => ['email'],
        'size' => 50,
        'appearance' => [
            // new options are "body", "cc", "bcc" and "subject"
            'allowedOptions' => ['body', 'cc'],
        ],
    ],
],

Impact

Editors now have more flexibility when creating links to emails in the TYPO3 backend.

Integrators have more flexibility when creating links within Fluid templates.